Rear Gunner XL – Part 4 – Movement

So far we’ve setup the variables we need, and drawn our sights and the enemy into the screen.  We still can’t really play the game though, as we need to have some way of moving around,  This is handled in lines 90 to 140:

; 90 IF INKEY$=“5” THEN LET B=B-1
; 100 IF INKEY$=“8” THEN LET B=B+1
; 110 IF INKEY$=“7” THEN LET A=A-1
; 120 IF INKEY$=“6” THEN LET A=A+1
; 130 IF INKEY$=“0” THEN GOTO 150
; 140 GOTO 50

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Racing (and other games) at Kempston

In most games, you’ll need to provide joystick control.  The Spectrum has quite a few different types of joystick interface – Protek/Cursor, Sinclair Interface 2, and Kempston – with Kempston being the most popular.  The Kempston interface is also special as it’s the only one of those which isn’t actually keyboard-based, and so is logically separate from controlling a game via keyboard.  It’s also pretty easy to use to! Continue reading